For purposes of this invention, complex carbohydrates are defined as any polymer comprising more than two sugar moieties and include such classes of compounds as polysaccharides and oligosaccharides. Polysaccharides include mucopolysaccharides and mannans whereas oligosaccharides are comprised of branched polysaccharides such as sialylated sugars including milk sugars. The key milk sugars (also called hexaoses) incorporated in the general class of complex carbohydrates are difucosyllacto-N-hexaose a and b, Disialyl-monofucosyllacto-N-hexaose and monofucosyllacto-N-hexsaose I, II, and II (obtainable from Oxford Glycosystems, Inc.).
One of the most active areas of research at present is the study of the genetics and function of mucopolysaccharides. These are glycosaminoglycans that can be obtained from numerous sources (e.g. rooster combs, trachea, umbilical cords, skin, articular fluids and certain bacteria such as Streptococci spp). Most glycosaminoglycans (hyaluronic acid, chondroitin sulfates A, B, and C, heparin sulfate, heparin, keratan sulfate, dermatan sulfate, etc.) are composed of repeating sugars such as n-acetylglucosamine, glucuronic acid and n-acetyl galactosamine (these are known as non-sulfated glycosaminoglycans). If such glycosaminoglycans contain sulfur groups they are known as sulfated glycosaminoglycans.
Heparin, hyaluronic acid and chondroitin sulfate are the most studied mucopolysaccharides. Heparin has been used for a number of years as an anticoagulant. Hyaluronic acid has been used therapeutically since the 1970s as a replacement for the vitreous humor of the eye post surgery and, more recently, as replacement for joint fluid in arthritic joints. The mode of action for hyaluronic acid injected directly into joints for treatment of arthritis has been proposed to be lubrication and replacement of the degraded joint fluid with highly viscous hyaluronic acid. High molecular weight (>750,000 daltons) and high viscosity have been reported to be critical for this use. (For purposes of this patent, all molecular weights are expressed as daltons. The unit designation will not be added hereinafter.) In the 1980s, it was discovered that chondroitin sulfate, or polysulfated glycosaminoglycan (known by its commercial name as ADEQUAN®) could be injected intramuscularly for reduction of pain and inflammation associated with arthrosis of horses. The mechanism of action of this glycosaminoglycan has been speculated to be inhibition of certain degradative enzymes present in the joint fluid that are up-regulated by trauma.
In the 1990s, chondroitin sulfate had developed into a popular nutritional supplement being used extensively to treat joint problems. Such treatment requires oral doses between 1000 and 3000 mg/day for humans. Even with these high doses (>15 mg/Kg), relief from joint pain often takes 6-9 months.
In 1989, it was discovered that intravenous, intramuscular or subcutaneous delivery of hyaluronic acid could reduce the pain of arthritis (U.S. Pat. No. 4,808,576 by Schultz et al) when the hyaluronic acid was delivered remote to the site of the arthritis (not into the joint). This Schultz et. al. patent specifically states that the hyaluronic acid must be of high purity (>99% pure hyaluronic acid). No mention is made of use of other complex carbohydrates, mucopolysaccharides or glycosaminoglycans administered by any method, or use of hyaluronate sodium orally or mucosally, use of low purity glycosaminoglycans or treatment of other diseases or conditions by parenteral administration.
The importance of high molecular weight for effectiveness of hyaluronic acid in the treatment of arthritis is generally emphasized (see for example Balazs, U.S. Pat. No. 4,141,973 and Howard and McIlraith, The Compendium, 15(3), March 1993) who summarize several clinical studies conducted to determine the most efficacious molecular weight range of hyaluronic acid injected intra-articularly to treat traumatic arthritis in horses. The conclusion from these studies was that hyaluronic acid with a molecular weight below 1×106 was not as effective as hyaluronic acid with a molecular weight above this value.
The most recent studies on hyaluronic acid discuss treatment of various types of cancer with very large doses of this macromolecule (Falk, WO 97/40841). This Falk application suggests that doses should exceed 750 mg per 70 Kg person, preferably, exceeding 1 g per 70 Kg person. This dose level calculates to be approximately 10-20 mg/Kg. Such doses are given intermittently post diagnosis and are not suggested to be preventative or administered in continuous low doses. Additionally, it is clear that the sodium hyaluronate of the Falk invention needs to be pure enough for injection even though oral administration is used in addition to intravenous injection. In all cases, patients were treated with hyaluronan in addition to chemotherapy. Hyaluronan was not used as the sole active ingredient for treatment of the cancer patients by Falk.
The adhesion cascade was first described in the early 1990s. In a summary by Adams and Shaw (The Lancet, 343, Apr. 2, 1994) the adhesion cascade is supposed to describe the mechanism by which pain and swelling are produced post trauma. It is divided into four sequential steps of tethering, triggering, strong adhesion and motility. Tethering interactions are mediated by a family of three lectin-like carbohydrate-binding molecules (selecting) These interactions are strong enough to cause the leukocytes to roll along the blood vessel walls to the site of trauma instead of flowing freely through such vessels as they would in a non-traumatized state. The triggering response is stimulated by factors such as cytokines stimulated by a traumatic event and mediated by adhesion molecules called integrins. Integrins, by themselves, do riot bind well to epithelium. However, when activated, integrins promote strong adhesion of the leukocyte to the epithelial surface Leukocytes bind to the epithelial cells via their receptor sites such as CD44, CD31, etc. By a mechanism of attachment and detachment the leukocytes are guided to the site of trauma. At the site of trauma the adhesion to the blood vessel wall becomes stronger and the interaction of these integrins with their ligands on the surface of the leukocytes are responsible for cessation of movement and flattening of the leukocyte. Finally, a process involving VCAM-1 and LFA-1 and other such integrins allows leukocytes to pass between endothelial cell junctions and into the tissue that has been traumatized. Collection of leukocytes at the site of trauma produces inflammation which is then followed by pain or other sequelae.
The metastatic cascade is very similar to the adhesion cascade. It has been proposed that tumor cells of all types contain CD44 receptor sites on their surface. These CD44 receptor sites appear to be involved in metastasis functioning similar to the receptor sites on leukocytes tethering the tumor cells to the blood vessel wall and providing the motility necessary for movement from one site to another in the mammalian body. A significant portion of the literature on CD44 and tumor cells/cancer teaches that hyaluronic acid or hyaluronan actually stimulates metastasis (Eur. J. Cancer, 1999, March; 35 (3), 473-480).
A coronary cascade has recently been described in the Harvard Health Letter (December 1999, pg. 4-5) and SCIENCE vol:285, Jul. 23, 1999, pg 595-599). This cascade describes a new mechanism to explain the development of heart disease and stroke. Rather than the traditional theory that plaques are formed by a collection of cholesterol alone, the new theory is based on the premise that there are stable and unstable plaques produced on blood vessel walls. Unstable plaques are the problem plaques because they are “swarming with T cells and macrophages” that are responding to a site of trauma and triggering the adhesion cascade resulting in inflammation. It is the “swarming T cells and macrophages” that make these plaques unstable. The T cells are described as sending macrophages a signal to release a protein called tissue factor which “spills out and encounters circulating blood, attracting platelets and triggering formation of a clot that quickly blocks up the artery”.
Accordingly, it is totally unexpected that complex carbohydrates of the present invention could be administered topically, orally, mucosally or parenterally, in low doses, to prevent and treat diseases and conditions associated with allergies, the adhesion cascade, the metastatic cascade and the coronary cascade described herein.